The present invention relates to a method of forming a composite ceramic material with fibrous structure, as well as the ceramic-ceramic material obtained by this method.
Particularly in the manufacture of ceramic thermomechanical parts intended for example for aeronautics, astronautics, the automobile industry or the furnace industry, composite materials are produced having a fibrous structure embedded in a ceramic material. For this, a porous, unidirectional or multidirectional (with two or three dimensions or random fiber distribution) structure is first of all formed using silicon carbide, alumina, silica, carbon or similar material fibers. The porosity of such a porous structure may, by volume, be about 40 to 90 %. then, the porous structure is embedded in a ceramic matrix.
So that the final ceramic material thus obtained has optimum mechanical and physical properties, its density must be as great as possible, i.e. the matrix must fill the pores of the fibrous structure to a maximum. That then means that, for the matrix, a material must be chosen whose viscosity (in solution or molten state) permits good penetration in the fibrous structure. The result is that some materials cannot be used for this reason as matrix. In addition, even when the material of the matrix is chosen from those likely to have adequate viscosity, in order to assist penetration of the porous structure by the more or less fluid material matrix, complex filling cycles need to be used and these cycles increased. This results in high manufacturing costs and delays. Finally, despite all these limitations and complications, the density of the material thus obtained by known methods cannot exceed an upper limit (not optimum for the desired properties of the material) because the surface pores of the structure are stopped up before the internal pores are filled. This results then in surface clogging preventing the complete filling of the porous structure by means of the material of the matrix.